Puella Magi Madoka Magica-2
In worlds where magic and wishes exist, it's even easier than usual to ask 'what if', but especially in a setting like this one the grass is not always greener on the other side.
This world lies four years in advance of the month covered in the original series wherein Madoka met Homura Akemi and her friends became magical girls. Only, there are several key differences with the other iteration of this world that exists on the MUSH: Walpurgis Night destroyed Mitakihara, all of the original team save the eponymous perished, and Homura's wish, rather than to go back in time to save Madoka, was that her friend could never become a witch. This has left Madoka in a position vaguely similar to Homura's in the original series.
Madoka has moved from city to city since the events of the events of the anime and encountered several new groups of magical girls, but is currently situated in the city of Higurekawa where she watches over Izumi Chou, Kazue Kiku, Mayumi Ume, and Eri Makoto. As one might expect, Kyubey has moved here as well, and is currently manipulating the situations of each one's life so that they will end up becoming magical girls and, inevitably, witches. Madoka and any visitors from the Multiverse are the only ones who could alter their fates, and the fate of their world as a whole.
Though it could have been inferred from the above, it bears some mention that, functionally, the state of the universe is precisely the same as it was before Madoka became the Law of Cycles. That is, magical girls still fight witches rather than demons, are still granted reality-altering wishes in exchange, and the Incubators are in the same position in relation to humanity as they always have been. Puella magi that fail to complete the tasks assigned them will have their soul gems gems become corrupt, and the only way to cure this corruption before it's too late is to use grief seeds, mystical objects that are found after witches are defeated.
Will things end more happily in this world, or will nothing change? Will the current group of magical girls live, or die? Only time will tell.
(For more detailed theme information and terminology, see the wiki page for Puella Magi Madoka Magica-1.)